Mitt Romney went to North Carolina to deliver a very early pre-rebuttal to the president’s convention. Romney’s tack is to tell voters what they “won’t hear”:

This is the approach of turning the president’s own words into an anchor around his neck. Romney says: “He set the measure; he has failed by the measurements he set.” So get ready for a lot of 2008 Obama campaign footage to show up — in Romney’s ads.

A few things are worth noting. The gap between promises and results is always a problem but when a candidate, as Obama was in 2008, is so grandiose in his vision and so determined to play the role of national game-changer, he makes the problem more acute for himself. The guy who promised his election would mark “the moment when we began to provide care for the sick and good jobs to the jobless . . . when the rise of the oceans began to slow and our planet began to heal” is going to be pained to explain why he’s come up so short.

Moreover, what does he do for a follow-up? Last time he promised to find jobs for the jobless, homes for the homeless, energy for the energyless, etc. so what does he do now — promise it all over again? Having not delivered makes it difficult to avoid repeating your own extravagances, at least not without reminding everyone you didn’t get it done in four years (or make much progress, for that matter).

And finally, it forces him to come up with more and more extravagant excuses to explain how badly he has fallen short. He has blamed George Bush, the GOP House and even the Founding Fathers. At some point it becomes ludicrous.

In sum, using Obama vs. Obama is a smart ploy for Romney to illustrate how badly he’s underperformed. And by the way, it’s a clever tactic with non-conservatives, who don’t have to agree that Obama failed to live up to Romney’s expectations; All they need do is see how he failed to live up to his own.